132 Maine Agricultural Experiment Station. 1918. 



There are, however, certain results available relating to the in- 

 heritance of external characters, chiefly color markings. It is 

 well known that in other animals certain economic characters 

 are frequently associated in inheritance with similar external 

 features. It is the purpose of this paper to present the avail- 

 able data on the inheritance of these external characters. In 

 later studies the question of the association of these with the 

 character of milk and fat production will be considered. 



The breeds used in the crosses are the Jersey, Guernsey, 

 Ayrshire and Holstein-Friesian for the dairy cattle and the 

 Aberdeen-Angus for the beef breed. 



The Detailed Analysis of the Inheritance of the Char- 

 acters in the First Generation Crosses. 



All of the animals which were used as parents in the forma- 

 tion of this first generation mendelian herd have long been pedi- 

 greed. 



Inbreeding studies by one of the methods devised in this 

 laboratory of the pedigrees of these parental pure bred animals 

 for four generations, showed the total number of repeated an- 

 cestors to be 36 and the total coefficient of inbreeding to be 

 225.00 percent. The average inbreeding per individual parent 

 of this herd up to the 4th generation, is then, only 9.00 percent. 

 In a previous study from this laboratory of the amount of in- 

 breeding found in pure bred Jersey cattle* it was shown that the 

 average minimum inbreeding coefficient of a sample of Jersey 

 bulls taken at random was 11. 01 percent and for the random 

 sample of the Jersey cows was 12.50 percent. For the advanced 

 registry Jersey bulls the minimum inbreeding was 14.88 percent 

 and the advanced registry Jersey cows was 9.23 percent. In 

 each case the inbreeding coefficient is higher than is that of the 

 foundation stock used to form the mendelian herd described in 

 this paper. Again the inbreeding coefficients of 14.50 and 9.23 

 represent the inbreeding coefficients of the highest producing 

 animals in the breed from which they were selected. Conse- 

 quently, it is held that since this percentage of inbreeding has not 



*Patterson, S. W., Investigation on the degree of inbreeding which 

 exists in American Jersey Cattle. Thesis publications of the University 

 of Maine, Orono. 



